Most of two-door type passenger vehicles are equipped behind the side doors with side windows each of which is hinged at its front edge to a suitable pillar such as a center pillar to be laterally swingably openable. Hitherto, the setting of such window at its desired opening and/or closing position has been achieved by using a conventional toggle link which has jointed two bars respectively connected at their leading ends to a free end portion of the window and the vehicle body. Although this toggle link is advantageous in providing tight setting of the window at the fully open position and at the fully closed position, it is impossible to tightly set the window at a desired partly open position. Furthermore, such link is disadvantageous in that the opening and closing operations of the window have to be made by a passenger who is seated just near the window. In other words, the operation of such window cannot be made by the driver who is positioned away from the window.